Orifice health detection device and method
A method of detecting orifice health includes moving a cap support into a drop detect position wherein a light source mounted on the cap support is positioned adjacent an array of fluid ejecting orifices, from the light source, projecting a light beam adjacent to the array of fluid ejecting orifices, ejecting at least one fluid drop from the array and through the light beam, and detecting scattered light from the at least one ejected fluid drop.
This application is a continuation in part of U.S. patent application Ser. No. 12/079,338, filed on Mar. 25, 2008, entitled A DROP DETECTION MECHANISM AND METHOD OF USE THEREOF, and hereby incorporated by reference herein.BACKGROUND
Printing devices, such as thermal ink jet printers, may include orifice plates including multiple orifices therein. A determination of orifice health, i.e., if an individual orifice is occluded, and if so, to what extent, and whether or not the ejection device of the individual orifice is functioning, may be periodically determined so as to schedule orifice plate maintenance and/or to compensate for the occluded orifice by use of another orifice during printing. Testing individual ones of the multiple orifices sequentially may be time consuming and may utilize expensive equipment.
The positioning of drop detection device 12 on cap structure 44 has many advantages. For example, use of cap motor 52 to move detection device 12 into a detection position (see
Similarly, during drop detection of drops 18 from first and second rows of die 58 and 60, respectively, light source 24 and light beam 22 may be aligned with first row of die 58 and second row of die 60, respectively, by movement of cap structure 44 by motor 52. In particular, motor 52 may move cap sled 48 into a first drop detection position (
Referring again to FIGS. 2 and 3A-3B, in one embodiment, first and second rows 58 and 60 of die together may extend across a width 74 of a print media path 76 of print zone 78, wherein print media path 76 and cap sled path 56 may be parallel to one another. Accordingly, array 14 may be referred to as a page wide array. In one embodiment, orifice plate 16 may not be moved in a direction parallel to width 74 as which may be the case in a printer including a movable carriage mounted printhead carriage rod. Accordingly, in the embodiment shown, array 14 may also be referred to as a fixed or a stationary printing array 14 because orifice plate 16 may remain stationary in its position with respect to print media path 76 and along width 74.
Page wide arrays differ from traditional movable print carriage printing systems. In particular, page wide arrays may not provide for manifold nozzle redundancy of scanning printing head engines, i.e., each nozzle 20 of a page wide array may be the sole ink printing orifice for a particular region of a page and, therefore, print quality may be degraded by occlusion of a single orifice 20. Print quality may be enhanced by a precise knowledge of the health of each nozzle 20 before starting printing of an image. Knowledge of an occluded or otherwise unhealthy print nozzle orifice in a page wide array may enable the writing system of the printer to apply a limited nozzle substitution so as to provide a high quality printed image.
Page wide array products may not be easily available in consumer and commercial printing markets because of the high complexity and stringent specifications of the writing system to support a high quality, ink printing page wide array that includes a nozzle health drop detector. However, because of the potential high productivity of such page wide arrays, the low noise generated by such page wide arrays, and the small form factors of page wide arrays, it may be desirable to provide a low cost page wide array printer for all printing market segments from consumer/office printers to digital presses. Providing a low cost page wide array printer may be feasible if a low cost drop detection device can be formulated for use in a page wide array printer.
Use of drop detectors has not heretofore been utilized in page wide printing arrays because of lack of experience, high complexity, high cost, and difficulties of scalability, i.e., providing a drop detector for the entire page wide array. Typically, drop detectors developed for traditional small and scanning printers are not scalable to page wide arrays because traditional drop detectors do not have a wide angle field of view. In particular, if the detector utilized is an electrostatic detector, such a page wide electrostatic detector would have a prohibitively large cost because of the noble metal coatings used on the detector. Moreover, if an electrostatic detector is utilized in a page wide array, such a detector would have an increased electrode area and would correspondingly increase the noise floor detection system utilized. Moreover, such large electrostatic detectors would not function reliably and therefore would be useless for page wide array applications. Accordingly, classical scanning drop detectors used in upscaled products are not reliable, are very slow, and do not meet the expectations of cost and performance. In other words, a page wide array electrostatic drop detector would have a huge footprint, which is a challenge for traditionally functioning electrostatic drop detectors.
In contrast, the light scattering optical system of the present invention is very scalable, and as no moving parts for the optical detector which renders the detector more reliable, which is important for large page wide array printers. Additionally, light guides 70 utilized in the light scattering optical system of the present invention are scalable for page wide arrays with little cost increase.
In printers including page wide arrays 14, each of the individual orifices 20 may be solely responsible for printing ink within its own individual region within width 74 of printzone 78. Accordingly, if a particular orifice 20a, also referred to as a nozzle, is fully or even partially occluded, the finished printed product may include an unprinted line extending along a length of the printed print media in a line parallel to the position of orifice 20a, for example. Accordingly, determining the health of each of the individual orifices 20 of array 14, i.e., whether or not the individual orifice 20 is occluded and if so to what extent, and if the ink ejection mechanism of the individual orifice is functioning, in such page wide arrays 14 may allow corrective measures to be taken to reduce or eliminate unprinted regions in the finished printed product. For example, if a particular orifice 20a is found by the printing orifice health detection device 12 to be occluded or the ejection device for the particular orifice is not functioning, servicing of the array 14 may be conducted, or adjacent orifices may be activated to eject ink therefrom to compensate for the non-functioning orifice.
Scattered light 26 may be directed as scattered light directly toward a light detection device 28, or as scattered light toward a light guide device 70, which is then projected to light detection device 28 by light guide device 70. Light guide device 70 may be a light pipe or a reflector, such as a mirror. Light detection device 28 may be a contact image sensor (CIS), which in one embodiment may be a complementary metal oxide semiconductor (CMOS) line array, or may be a photo diode. A predetermined low threshold light intensity may indicate the presence of an ink drop 18 and a predetermined high threshold light intensity may indicate the absence of an ink drop 18. In the embodiment shown in
In other embodiments, other shapes, locations, angles, and the like of the components, or other components, of the system may be utilized for the determination of orifice health.
Other variations and modifications of the concepts described herein may be utilized and fall within the scope of the claims below.
1. An orifice health detection device, comprising:
- an array of fluid ejecting orifices, each of said fluid ejecting orifices configured to eject at least one fluid drop;
- a light source that produces a light beam configured to scatter light from said at least one ejected fluid drop;
- a light detector configured to detect scattered light from said at least one ejected fluid drop; and
- a cap structure adapted for capping said fluid ejecting orifices, wherein said light source and said light detector are mounted on said cap structure.
2. The device of claim 1 wherein said array is a page wide array.
3. The device of claim 1 further comprising a motor connected to said cap structure and adapted for moving said cap structure, and said light source and said light detector mounted thereon, with respect to said array.
4. The device of claim 1 wherein said cap structure includes a fluid repository, and wherein said light beam is projected over said fluid repository such that a fluid drop ejected by said array and into said repository passes through said light beam.
5. The device of claim 3 wherein said array is positioned above a print media path, and wherein said motor is adapted for moving said light source and said light detector in a direction parallel to said print media path.
6. The device of claim 1 further comprising a light guide positioned adjacent to said light beam, said light guide configured to direct said scattered light to said light detector.
7. The device of claim 6 wherein said light guide is chosen from the group consisting of a light pipe and a reflective device.
8. The device of claim I wherein said light source includes at least one laser light source.
9. The device of claim I wherein said light detector is chosen from the group consisting of a contact image sensor and a photodiode.
10. The device of claim 1 wherein said array comprises a plurality of die extending across a width of a printzone.
11. The device of claim I further comprising a controller that receives light scattering information detected by said light detector, said controller utilizing said light scattering information to determine a health of an orifice that ejected said at least one ejected fluid drop.
12. A method of detecting orifice health, comprising:
- moving a cap support into a drop detect position wherein a light source mounted on said cap support is positioned adjacent an array of fluid ejecting orifices;
- from said light source, projecting a light beam adjacent to said array of fluid ejecting orifices;
- ejecting at least one fluid drop from said array and through said light beam; and
- detecting scattered light from said at least one ejected fluid drop.
13. The method of claim 12 further comprising utilizing said detected scattered light to determine a health of an orifice that ejected said at least one ejected ink drop.
14. The method of claim 12 further comprising collecting said scattered light in a light collector, and wherein said step of detecting detects said scattered light from said light collector.
15. The method of claim 13 wherein said step of ejecting comprises simultaneously ejecting fluid drops from multiple orifices of said array, wherein said step of detecting comprises detecting light scattered from said fluid drops from multiple orifices, and further comprising utilizing said detected scattered light to determine a health of each orifice that ejected individual ones of said ejected fluid drops.
16. The method of claim 12 wherein said moving a cap support comprises moving said cap support in a direction parallel to a print media path.
17. A method of manufacturing a drop detection device, comprising:
- providing an array of fluid ejecting orifices, said fluid ejecting orifices configured to eject at least one fluid drop;
- providing a cap structure adapted for capping said array, said cap structure including a light source and a light detector positioned thereon;
- said light source adapted to produce a light beam configured to scatter light from said at least one ejected fluid drop; and
- said light detector adapted to detect scattered light from said at least one ejected fluid drop.
18. The method of claim 17 further comprising positioning a light guide on said cap structure so as to direct said scattered light to said light detector.
19. The method of claim 17 further comprising connecting a controller to said light detector, said controller configured to determine a health of an orifice that ejected said at least one ejected fluid drop based on said detected scattered light.
20. The method of claim 17 further comprising connecting a motor to said cap structure, said motor adapted for moving said cap structure into a capping position on said array and into a light detection position adjacent said array.